For this section, every energy saving feature was enabled in the respective BIOSes and the Windows 7's power plan was changed from High Performance to Balanced.

For our idle test, we let the system idle for 15 minutes and measured the peak wattage through our UPM EM100 power meter.

For our CPU load test, we ran Prime 95 In-place large FFTs on all available threads for 15 minutes, measuring the peak wattage via the UPM EM100 power meter.

For our overall system load test, we ran Prime 95 In-place large FFTs on all available threads for 15 minutes, while simultaneously loading the GPU with OCCT v3.1.0 GPU:OCCT stress test at 1680x1050@60Hz in full screen mode.

Compared to its main competition, the i7-2600K, the i7-3820 has about 10% higher idle and 20% higher CPU load power consumption. This is a significant increase, but one must keep in mind that the Sandy Bridge-E chip does have 25% more power-sucking L3 cache, a much larger integrated memory controller, and a revamped PCI-E controlller. You aren't really getting much additional pure CPU performance for those extra watts, but they are an end result of the greatly enhanced PCI-E bandwidth capabilities of the chipset.

Temperature Testing

For the temperature testing, we used the Intel Thermal Solution RTS2011LC liquid cooler and Prolimatech Mega Shadow. The ambient temperature was 22°C/71.6°F. The application used to monitor temperatures was HWiNFO v3.82-1300. Keep in mind that the thermal sensors in most modern processors are not really accurate at measuring idle temperatures, hence the very small delta between the room temp and the idle results.

Idle: The system was left to idle for 15 minutes.
Load: Prime 95 In-place large FFTs was run for 15 minutes.

The Thermal Solution RTS2011LC proved to be an exceptionally quiet-running cooler, with the fan nearly always running at a silent 878RPM. In auto mode, we saw it peak at 958RPM a few times when the system was fully loaded for 15 minutes, but obviously even that was inaudible. We actually had to go in the bios to set 100% fan speed to get the above result. At that level, the fan spins at 2200 RPM, pushes about 73CFM, and outputs roughly 35 dBA. Its definitely not a terrible cooler, but since it retails for $80 that pushes it into Corsair Hydro H70 territory, which is a better performing product.